Fixed constructors of DistributedVectorView

   using BaseType::DistributedArrayView;

   using BaseType::operator=;

   // In C++14, default constructors cannot be inherited, although Clang

   // and GCC since version 7.0 inherit them.

   // https://stackoverflow.com/a/51854172

   __cuda_callable__

   DistributedVectorView() = default;

   // initialization by base class is not a copy constructor so it has to be explicit

   template< typename Real_ >  // template catches both const and non-const qualified Element

   __cuda_callable__

   DistributedVectorView( const DistributedArrayView< Real_, Device, Index, Communicator >& view )

   : BaseType::DistributedArrayView( view ) {}

   LocalVectorViewType getLocalVectorView();

   ConstLocalVectorViewType getLocalVectorView() const;